View Full Version : Distance Point\Plane

01-19-2002, 02:33 PM
Ho to all!

Is there a way to compute point\plane distance if i only know point P coordinates and that the plane lays on ZY? (so x=0)


01-19-2002, 04:19 PM
distance to the plane is simply the evaluation of plane equation using the point. If you do the math on paper you will see.

so in your case, the plane equation is :

1x = Distance; normal is (1,0,0) it could also be (-1,0,0); or if you want

1x + 0y + 0z + 0 = Distance (generic plane equation is : Ax + By + Cz + D = distanceToPlane)

As you can see if the point is on the plane then the distance = 0;

if the distance > 0 than the point lies on the side pointed by the normal with distance being the distance.

If distance is negative, then you are simply on the other side of the plane.

01-19-2002, 10:19 PM
So in particular cases that plane lays on ZY,XY,XZ distance will be given by:

P = point
ZY Distance = |P.X|;
XY Distance = |P.Z|;
XZ Distance = |P.Y|;